package km.TestCrypto;
	import java.security.SecureRandom;   
	import javax.crypto.Cipher;   
	import javax.crypto.KeyGenerator;   
	import javax.crypto.SecretKey;   
	import javax.crypto.spec.SecretKeySpec;   
	  
	  
	 /** * Usage: *  
	 * String crypto = SimpleCrypto.encrypt(masterpassword, cleartext)  
	 * ...  
	 * String cleartext = SimpleCrypto.decrypt(masterpassword, crypto)  
	 *   
	* @author ferenc.hechler */  
	  
	public class SimpleCrypto   
	{
//		public static void main(String[] args) {
//			try{
//				String enctypt =encrypt("aaaa","bbbb");
//			System.out.println("enctypt>>>>:"+enctypt);
//			System.out.println("decrypt	>>>>:"+decrypt("aaaa",enctypt));
//					
//			}catch(Exception e){
//				e.printStackTrace();				
//			}
//		}
	 public static String encrypt(String seed, String cleartext) throws Exception   
	{   
	 byte[] rawKey = getRawKey(seed.getBytes());   
	 byte[] result = encrypt(rawKey, cleartext.getBytes());   
	 return toHex(result);   
	 }   
	  
	  
	 public static String decrypt(String seed, String encrypted) throws Exception   
	{   
	 byte[] rawKey = getRawKey(seed.getBytes());   
	 byte[] enc = toByte(encrypted);   
	 byte[] result = decrypt(rawKey, enc);   
	 return new String(result);   
	 }   
	  
	  
	 private static byte[] getRawKey(byte[] seed) throws Exception 
	 {   
//	 KeyGenerator kgen = KeyGenerator.getInstance("AES");   
//	 SecureRandom sr = SecureRandom.getInstance("SHA1PRNG");   
	 KeyGenerator kgen = KeyGenerator.getInstance("AES");   
	 SecureRandom sr = SecureRandom.getInstance("SHA1PRNG");   
	 sr.setSeed(seed);   
	 kgen.init(128, sr);   
	// 192 and 256 bits may not be available   
	  
	  
	 SecretKey skey = kgen.generateKey();   
	 byte[] raw = skey.getEncoded();   
	 return raw;   
	 }   
	  
	  
	 private static byte[] encrypt(byte[] raw, byte[] clear) throws Exception   
	{   
	 SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");   
	 Cipher cipher = Cipher.getInstance("AES");   
	 cipher.init(Cipher.ENCRYPT_MODE, skeySpec);   
	 byte[] encrypted = cipher.doFinal(clear);   
	 return encrypted;   
	 }   
	  
	  
	 private static byte[] decrypt(byte[] raw, byte[] encrypted) throws Exception   
	{   
	 SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");   
	 Cipher cipher = Cipher.getInstance("AES");   
	 cipher.init(Cipher.DECRYPT_MODE, skeySpec);   
	 byte[] decrypted = cipher.doFinal(encrypted);   
	 return decrypted;   
	 }   
	  
	  
	 public static String toHex(String txt)   
	{   
	 return toHex(txt.getBytes());   
	 }   
	  
	  
	 public static String fromHex(String hex)   
	{   
	 return new String(toByte(hex));   
	 }   
	  
	  
	 public static byte[] toByte(String hexString)   
	{   
	 int len = hexString.length()/2;   
	 byte[] result = new byte[len];   
	  
	  
	 for (int i = 0; i < len; i++) result[i] =    
	Integer.valueOf(hexString.substring(2*i, 2*i+2), 16).byteValue();   
	 return result;   
	 }   
	  
	  
	 public static String toHex(byte[] buf)   
	{   
	 if (buf == null) return "";   
	 StringBuffer result = new StringBuffer(2*buf.length);   
	  
	  
	 for (int i = 0; i < buf.length; i++)   
	{   
	 appendHex(result, buf[i]);   
	 }   
	  
	  
	 return result.toString();   
	 }   
	  
	  
	 private final static String HEX = "0123456789ABCDEF";   
	  
	  
	private static void appendHex(StringBuffer sb, byte b)   
	{   
	 sb.append(HEX.charAt((b>>4)&0x0f)).append(HEX.charAt(b&0x0f));   
	 }   
	 }  
